This invention relates in general to braking systems and, more particularly, to a system operable to apply or maintain the application of a vehicle's brakes while a vehicle door is open and to continue to maintain the brakes in an applied condition for a predetermined period of time after the door has been closed.
Numerous injuries and deaths are caused each year by vehicles striking individuals who are waiting to board or who have disembarked from the vehicle. This problem is particularly acute with school buses transporting school children. While the children are often instructed on the proper procedures for getting on and off the school bus, they frequently disobey such instructions and move into the path of the bus. At other times, the children stumble as they disembark and are struck by the rear wheels of the bus if the driver pulls away from the stop without checking to make sure the child has moved a safe distance from the bus. Injuries have also been known to occur when the child's clothing or book bag becomes caught in the vehicle door and the bus pulls away before the driver notices the entangled child. In addition, when a bus is stopped on an incline, a driver preoccupied with opening and closing the door may fail to maintain firm pressure on the brake pedal and the resulting movement of the bus may also result in injury to those in the vicinity of the bus.
A prior attempt to limit such injuries has focused on a system which automatically applies the vehicle brakes when the vehicle has slowed to a predetermined speed. This system has an obvious disadvantage in that the vehicle is forced to stop regardless of whether the vehicle has slowed because of the flow of traffic or is stopping to let off passengers. Other systems have interlocked the brakes and the vehicle doors so that the brakes are applied and cannot be released when the doors are open. While these systems may prevent inadvertent movement of the vehicle when the doors are open, they do not prevent injuries which result after the door has closed and the driver pulls away before a disembarking passenger has moved a safe distance from the vehicle.